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81.
Wavelet processing and digital interferometric contrast to improve reconstructions from X‐ray Gabor holograms 下载免费PDF全文
Juan C. Aguilar Masaki Misawa Kiyofumi Matsuda Yoshio Suzuki Akihisa Takeuchi Masato Yasumoto 《Journal of synchrotron radiation》2018,25(3):808-817
In this work, the application of an undecimated wavelet transformation together with digital interferometric contrast to improve the resulting reconstructions in a digital hard X‐ray Gabor holographic microscope is shown. Specifically, the starlet transform is used together with digital Zernike contrast. With this contrast, the results show that only a small set of scales from the hologram are, in effect, useful, and it is possible to enhance the details of the reconstruction. 相似文献
82.
Dr. Sudhir Kumar Keshri Dr. Waka Nakanishi Dr. Atsuro Takai Prof. Dr. Tomoya Ishizuka Prof. Dr. Takahiko Kojima Prof. Dr. Masayuki Takeuchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13288-13294
The design and synthesis of a tweezer-shaped naphthalenediimide (NDI)–anthracene conjugate ( 2NDI ) are reported. In the structure of the closed form (πNDI ⋅⋅⋅ πNDI stack) of 2NDI , which was elucidated by single-crystal XRD, the existence of C−H ⋅⋅⋅ O hydrogen bonding involving the nearest carbonyl oxygen atom of an NDI unit was suggested. The tunability of πNDI ⋅⋅⋅ πNDI interactions was studied by means of UV/Vis absorption, fluorescence and NMR spectroscopy and molecular modelling. This revealed that the πNDI ⋅⋅⋅ πNDI interactions in 2NDI affect the absorption and emission properties depending on the temperature. Furthermore, in polar solvents, 2NDI prefers the stronger πNDI ⋅⋅⋅ πNDI stack, whereas the πNDI ⋅⋅⋅ πNDI interaction is diminished in nonpolar solvents. Importantly, the conformational variations of 2NDI can be reversibly switched by variation in temperature, and this suggests potential application for fluorogenic molecular switches upon temperature changes. 相似文献
83.
Tomohito Kameda Hidenori Takeuchi Toshiaki Yoshioka 《Journal of Physics and Chemistry of Solids》2009,70(7):1104-1083
New layered magnesium hydroxides whose brucite layers had been bridged with malate2− and tartrate2− were prepared by dropwise addition of Mg(NO3)2 to malate and tartrate solutions at a constant pH of 10.5. Malate2− and tartrate2− may have been also absorbed on the surfaces of hydroxides. In the case of using citrate solution, Mg(OH)2 absorbed with citrate3− was produced. These materials were found to take up Cu2+ rapidly from an aqueous solution at pH 5.0. Copper uptake by precipitates is attributed to the formation of chelate complexes of Cu2+ with citrate3−, malate2−, and tartrate2−. 相似文献
84.
Yoichi Sakai Satoru Onaka Masashi Takahashi Ryo Ogiso Tsutomu Takayama Tadahiro Nakamoto 《Hyperfine Interactions》2012,207(1-3):1-5
Magnetorheological (MR) fluids are new iron-based materials, whose applications include brakes, dampers, clutches, shock absorbers systems and polishing of optical surfaces (lens and mirrors). They are dependent on the size and shape of particles as the magnetic properties. Interested in the possibility of using iron-rich powders, commonly used in nondestructive testing, ranging in size from a few μm to about 200?μm and lower cost than those commercially used for MR fluids, a study of the structural and magnetic properties of iron-rich metallic particles by X-ray diffraction (XRD) and M?ssbauer spectroscopy (MS) at room temperature has been done. Powders, as received, were separated into particle sizes smaller than 20?μm (sample A) and in the range of 20–38?μm (sample B) because these are the sizes generally required for applications in MR fluids. The particles whose sizes exceed the above values were ground in a high energy planetary mill for 3?h, using different values of rotational speed/time: 200?rpm for one hour, a pause of 10?s, 140?rpm for one hour, pause 10?s and then 175?rpm during the last hour. These powders were sieved to obtain particles smaller than 20?μm (sample C). According XRD results, in all samples, only α-Fe (lattice parameter a = 2,867(2) ?) and Fe2O3 (lattice parameter a = 5,037(1) ? and c = 13,755(8) ?) were present. The M?ssbauer spectra were fitted with two sextets. The hyperfine parameters values allowed us to assign the highest relative area spectrum (sextet) corresponding to α-Fe and the second one to Fe2O3 in accord to the XRD results. Thus, the preparation method using mechanical milling for diminishing the size of the metallic particles allowed us to get particles with size and magnetic properties that could lead to potentially MR fluids applications. 相似文献
85.
Atsunori Matsuda Masahiro Tatsumisago Tsutomu Minami 《Journal of Sol-Gel Science and Technology》2000,19(1-3):581-584
Silica gels doped with several protonic acids such as HClO4, H2SO4 and H3PO4 have been prepared by the sol-gel method and totally solid electric double-layer capacitors have been successfully fabricated using the highly proton-conductive silica gels as an electrolyte and activated carbon powder (ACP) hybridized with the silica gels as a polarizable electrode. It was found that the addition of HClO4, which had the highest value of acid dissociation constant among these three acids, most effectively increased the proton conductivity of the resultant acid-doped silica gels. Tablets of the HClO4-doped silica gels exhibited conductivities as high as 10–5–10–2 S cm–1 at room temperature in dry N2 atmosphere. One of the capacitors fabricated using the protonic acid-doped silica gels had a capacitance of 44 F/(gram of total ACP in the capacitor), which was comparable to those of conventional capacitors using liquid electrolytes. 相似文献
86.
Hamao Watanabe Kazuaki Higuchi Tomoko Goto Tsutomu Muraoka Jun Inose Masaaki Kageyama Yasuko Iizuka Masakatsu Nozaki Yoichiro Nagai 《Journal of organometallic chemistry》1981,218(1):27-39
In the presence of a catalytic amount of sodium methoxide, sym-dimethoxytetramethyldisilane was converted into α,ω-dimethoxypermethylpolysilanes, MeO(SiMe2)nOMe where n ? 3, at room temperature. On the other hand, similar treatment of the disilane in THF solution gave cyclic polysilanes, (Me2Si)n where n = 5–7. Decomposition of the disilane in the presence of diphenylacetylene afforded a trisilacyclopentene derivative under similar conditions. This compound was obtained also by the reaction between α,ω-dimethoxypermethylpolysilanes and diphenylacetylene in the presence of sodium methoxide. These cyclic products most likely were formed via permethyl polysilyl anion intermediates derived from α,ω-dimethoxypermethylpolysilanes. Also, the formation of α,ω-dimethoxypermethylpolysilanes could be elucidated in terms of the mechanism involving the base-assisted, concerted nucleophilic substitution or stepwise substitution by silyl anions, rather than the successive dimethylsilylene (Me2Si:) insertion reaction. 相似文献
87.
Kumondai K Toyoda M Ishihara M Katakuse I Takeuchi T Ikeda M Iwamoto K 《The Journal of chemical physics》2005,123(2):24314
The reaction mechanisms of silver trimer cation, Ag3+, with 12-crown-4 (12C4) were studied experimentally and theoretically. Using a cylindrical ion trap time-of-flight mass spectrometer, gas-phase ion/molecule reactions of Ag3+ with 12C4 were observed. Metal-ligand complexes of [Ag(12C4)]+, [Ag3(12C4)]+ and [Ag3(12C4)2]+, and of [Ag(12C4)2]+ and [Ag3(12C4)3]+, were observed as the reaction intermediates and terminal products, respectively. The formations of the [Ag12C4]+ and [Ag(12C4)2]+ complexes indicated that the neutral dimer (Ag2) had been eliminated from the trimer cation. From the results of ab initio calculations at the HF/LanL2DZ level of theory and the experiments, it is suggested that three 12C4 molecules can attach to Ag3+ through consecutive reactions and that neutral Ag2 can be easily eliminated from [Ag3(12C4)]+. 相似文献
88.
The reaction of 5a-acetyl-6-ethoxycarbonyl-5a,6a-dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitrile ( 1a ) with benzylamine gave ethyl l-benzyl-5-cyano-8a,9-dihydro-2-methyl-1H-pyrrolo[3,4-e]-pyrazolo[1,5-a]pyrimidine-8a-carboxylate ( 2a ), in addition to 5-acetyl-3-benzylamino-1-(4-cyanopyrazol-3-yl)- 2-pyridone ( 3 ). Reaction of 1a with aniline gave ethyl 6-acetyl-8-anilino-3-cyano-7,8-dihydro-4H-pyrazolo-[1,5-a][1,3]diazepine-8-carboxylate ( 4 ), in addition to ethyl 3-cyano-7-methyl-6-pyrazolo[1,5-a]pyrimidine-acrylate ( 5 ). On the other hand, the same reactions of 1b with benzylamine or aniline gave 2b or 8b , respectively. Though catalytic hydrogenation of 1a over 5% palladium-carbon proceeded by ring fission of cyclopropane ring to give 9 , 1a (or 1b ) afforded 4,5-dihydro derivatives ( 13 or 15 ) by catalytic hydrogenation over platinum oxide. The reactivity of 5-methoxy-4,5,5a,6a-tetrahydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine ( 16 ), which are related analogs of 1a,b , is also described. 相似文献
89.
90.
A Programmable Signaling Molecular Recognition Nanocavity Prepared by Molecular Imprinting and Post‐Imprinting Modifications 下载免费PDF全文
Ryo Horikawa Dr. Hirobumi Sunayama Dr. Yukiya Kitayama Dr. Eri Takano Prof. Dr. Toshifumi Takeuchi 《Angewandte Chemie (International ed. in English)》2016,55(42):13023-13027
Inspired by biosystems, a process is proposed for preparing next‐generation artificial polymer receptors with molecular recognition abilities capable of programmable site‐directed modification following construction of nanocavities to provide multi‐functionality. The proposed strategy involves strictly regulated multi‐step chemical modifications: 1) fabrication of scaffolds by molecular imprinting for use as molecular recognition fields possessing reactive sites for further modifications at pre‐determined positions, and 2) conjugation of appropriate functional groups with the reactive sites by post‐imprinting modifications to develop programmed functionalizations designed prior to polymerization, allowing independent introduction of multiple functional groups. The proposed strategy holds promise as a reliable, affordable, and versatile approach, facilitating the emergence of polymer‐based artificial antibodies bearing desirable functions that are beyond those of natural antibodies. 相似文献